[Source: PLoS One, full page: (LINK). Abstract, edited.]
OPEN ACCESS / PEER-REVIEWED / RESEARCH ARTICLE
Severe cases of seasonal influenza in Russia in 2017-2018
Natalia P. Kolosova , Tatyana N. Ilyicheva , Alexey V. Danilenko, Julia A. Bulanovich, Svetlana V. Svyatchenko, Alexander G. Durymanov, Natalia I. Goncharova, Andrei S. Gudymo, Alexander N. Shvalov, Ivan M. Susloparov, Vasiliy Y. Marchenko, Tatyana V. Tregubchak, Elena V. Gavrilova, Rinat A. Maksyutov, Alexander B. Ryzhikov
Published: July 29, 2019 / DOI: https://doi.org/10.1371/journal.pone.0220401
The 2017–2018 influenza epidemic season in Russia was characterized by a relatively low morbidity and mortality. We evaluated herd immunity prior to the 2017–2018 influenza season in hemagglutination inhibition assay, and performed characterization of influenza viruses isolated from severe or fatal influenza cases and from influenza cases in people vaccinated in the fall of 2017. During the 2017–2018 epidemic season, 87 influenza A and B viruses were isolated and viruses of the 75 influenza cases, including selected viral isolates and viruses analyzed directly from the original clinical material, were genetically characterized. The analyzed A(H1N1)pdm09 viruses belonged to clade 6B.1, B/Yamagata-like viruses belonged to clade 3, and B/Victoria-like viruses belonged to clade 1A and they were antigenically similar to the corresponding vaccine strains. A(H3N2) viruses belonged to clade 3C.2a and were difficult to characterize antigenically and the analysis indicated antigenic differences from the corresponding egg-grown vaccine strain. The next generation sequencing revealed the presence of D222/G/N polymorphism in the hemagglutinin gene in 32% of the analyzed A(H1N1)pdm09 lethal cases. This study demonstrated the importance of monitoring D222G/N polymorphism, including detection of minor viral variants with the mutations, in the hemagglutinin gene of A(H1N1)pdm09 for epidemiological surveillance. One strain of influenza virus A(H1N1)pdm09 was resistant to oseltamivir and had the H275Y amino acid substitution in the NA protein. All other isolates were susceptible to NA inhibitors. Prior to the 2017–2018 epidemic season, 67.4 million people were vaccinated, which accounted for 46.6% of the country’s population. Just before the epidemic season 33–47% and 24–30% of blood sera samples collected within the territory of Russia showed the presence of protective antibody titers against vaccine strains of influenza A and influenza B/Victoria-like, respectively. Mass vaccination of the population had evidently reduced the severity of the flu epidemic during the 2017–2018 influenza epidemic season in Russia.
Citation: Kolosova NP, Ilyicheva TN, Danilenko AV, Bulanovich JA, Svyatchenko SV, Durymanov AG, et al. (2019) Severe cases of seasonal influenza in Russia in 2017-2018. PLoS ONE 14(7): e0220401. https://doi.org/10.1371/journal.pone.0220401
Editor: Florian Krammer, Icahn School of Medicine at Mount Sinai, UNITED STATES
Received: March 14, 2019; Accepted: July 14, 2019; Published: July 29, 2019
Copyright: © 2019 Kolosova et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: This work was supported by State Assignments no. 1/16 and 2/18 (FBRI SRC VB VECTOR, Rospotrebnadzor), http://www.vector.nsc.ru/. The funders supported obtaining a number of reagents, funded sequencing and HI tests, data analysis and covered publication fees.
Competing interests: The authors have declared that no competing interests exist.
Keywords: Seasonal Influenza; Russia.